1. Field of the Invention
The present invention relates to a gas analyzer and a gas-analyzing mechanism, in particular to an improvement of a non dispersive infrared analyzer capable of simultaneously detecting a plurality of components in a single-cell mode and a gas analyzer unit suitable for simultaneously detecting a plurality of components in a cross-flow modulation single-cell mode where a plurality of non dispersive infrared analyzers are used in combination.
2. Description of the Prior Art
A non dispersive infrared analyzer (hereinafter referred to as NDIR) has been generally used in a single-optical path single-component detection mode. In the case where a plurality of components are measured, even in case of a single-cell mode, two-optical path two-component detection mode is adopted and as a result, a large number of optical parts are required. In addition, in order to simultaneously measure 3 components or 4 components, even though a cross-flow modulation single-cell mode, in which a sample gas and a reference gas are alternately introduced into two cells through a rotary valve, is used, it is necessary to prepare two gas analyzer units and two series of flow rate of said sample gas from a sampling device. Consequently, not only for example a sampling flow rate is increased, a number of optical parts being increased, and a sampling system being complicated and thus manufacturing expenses are increased but also the maintenance of a plurality of analyzers is required and thus also a running cost is increased. In addition, in a light-intermitting mode, a problem has occurred also in for example a response-delay (in case of being connected in series).